3GPP-Rel18 branch: C++ mustache template fixes

[davidjwbbc]

This adds some extra handling for composed types to account for the 3GPP definitions of objects used in MBSTF packet operating mode.

This also adds an override for TS29571_CommonData.yaml to merge multiple string patterns into one pattern so that openapi-generator can handle it. It changes some entries that look like:

Object:
  type: string
  allOf:
    - pattern: "<regex1>"
    - pattern: "<regex2>"

...to:

Object:
  type: string
  pattern: "<intersection regex for regex1 and regex2>"

[rjb1000]

This also adds an override for TS29571_CommonData.yaml to merge multiple string patterns into one pattern so that openapi-generator can handle it.

Was it just too difficult to code that intersection of two regular expressions in the Mustache template, @davidjwbbc?

[davidjwbbc]

This also adds an override for TS29571_CommonData.yaml to merge multiple string patterns into one pattern so that openapi-generator can handle it.

Was it just too difficult to code that intersection of two regular expressions in the Mustache template, @davidjwbbc?

It's not that it's difficult, in fact it's quite easy, it's more that openapi-generator doesn't present the multiple patterns in the object model it presents to the mustache templates. So there's nothing for the templates to use to generate appropriate code.